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王凯, 张振南, 秦爱芳. 考虑微观莫尔-库仑准则的拓展虚内键本构模型[J]. 岩土工程学报, 2014, 36(5): 880-885. DOI: 10.11779/CJGE201405010
引用本文: 王凯, 张振南, 秦爱芳. 考虑微观莫尔-库仑准则的拓展虚内键本构模型[J]. 岩土工程学报, 2014, 36(5): 880-885. DOI: 10.11779/CJGE201405010
WANG Kai, ZHANG Zhen-nan, QIN Ai-fang. Augmented virtual internal bond considering micro Mohr-Coulomb criterion[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(5): 880-885. DOI: 10.11779/CJGE201405010
Citation: WANG Kai, ZHANG Zhen-nan, QIN Ai-fang. Augmented virtual internal bond considering micro Mohr-Coulomb criterion[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(5): 880-885. DOI: 10.11779/CJGE201405010

考虑微观莫尔-库仑准则的拓展虚内键本构模型

Augmented virtual internal bond considering micro Mohr-Coulomb criterion

  • 摘要: 拓展虚内键本构模型(augmented virtual internal bond-AVIB)蕴含了微观断裂机理,在模拟材料断裂破坏过程中有着较强的优势,它还不能很好地模拟岩土材料的压剪破坏的力学行为,这限制了它在岩土工程中的应用。为了突破这一局限性,在微观虚内键层面上引入了莫尔-库仑类型的虚内键破坏准则,来模拟岩土材料宏观压剪破坏行为。数值分析表明:通过引入这一微观莫尔-库仑准则,可以很好地再现岩石材料三轴受压情况下的强度特征,并且在大量数值模拟基础上,得出了微观内摩擦角和黏聚力与宏观内摩擦角和黏聚力之间的关系。该关系为本模型的参数标定提供了依据。

     

    Abstract: The augmented virtual internal bond (AVIB) is a multiscale constitutive model developed from the virtual internal bond (VIB). VIB considers solid materials to consist of randomized ‘material particles’ in a micro scale. The material particles are connected with VIB. AVIB uses the Xu-Needleman potential function to simultaneously account for the energy contribution of normal and shear deformations of a micro bond. Because the micro fracture mechanism has been implicitly embedded into the constitutive relation of AVIB, AVIB presents many advantages in simulating the fracture propagation of materials. Although the AVIB can successfully simulate the tensile fracture propagation, it cannot simulate the compressive-shear failure behaviors of geomaterials. The underlying reason lies in that the Xu-Needleman potential function cannot describe the micro contact properties of granular materials. To break this limitation of AVIB, a Mohr-Coulomb type of rupture criterion is introduced for compressive bond. Through the micro Mohr-Coulomb criterion, AVIB can capture the key failure mechanism of geo-materials subjected to compression and shear. Through numerical simulation, it is found that the micro cohesive strength governs the macro cohesive strength of geomaterials and the micro friction angle governs the macro friction angle. A linear relationship exists between the micro and macro cohesive strengths, and the micro and macro friction angles. There is no correlation between the micro cohesive strength and macro friction angle, and the micro friction angle and macro cohesive strength. The simulation example suggests that the triaxial strength of rock is linear with the confining pressure, which agrees with the observation in experiment. This demonstrates that the proposed method is valid. It may provide a new micro mechanics constitutive model for geomaterials.

     

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